When attempting to link XDP prog with MTU larger than supported,
user is not informed why XDP linking fails. Adding proper
error message: "MTU too large to enable XDP".
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com> Signed-off-by: Eryk Rybak <eryk.roch.rybak@intel.com> Tested-by: Kiran Bhandare <kiranx.bhandare@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>